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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

1415 results found.

  1. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  2. LIGO/Virgo/KAGRA S240930df: 1 counterpart neutrino candidate event from an IceCube neutrino search
  3. AMON NuEM 240926A: Swift XRT Follow-up
  4. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  5. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240926A
  6. GRB 240825A: Upper limits from a neutrino search with IceCube
  7. IceCube-240721A: AT2023qqp and AT2024pge likely unrelated
  8. IceCube-240808A: Upper limits from a search for additional neutrino events in IceCube
  9. Fermi-LAT gamma-ray observations of IceCube-240808A
  10. IceCube Alert 240808.27: Global MASTER-Net observations report
  11. IceCube-240808A - IceCube observation of a high-energy neutrino candidate track-like event
  12. IceCube-240725A: Upper limits from a search for additional neutrino events in IceCube
  13. Fermi-LAT gamma-ray observations of IceCube-240725A
  14. IceCube Alert 240725.22: Global MASTER-Net observations report
  15. IceCube-240725A - IceCube observation of a high-energy neutrino candidate track-like event
  16. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  17. IceCube-240721A: Upper limits from a search for additional neutrino events in IceCube
  18. Fermi-LAT gamma-ray observations of IceCube-240721A
  19. IceCube-240721A - IceCube observation of a high-energy neutrino candidate track-like event
  20. IceCube Alert 240721.68: Global MASTER-Net observations report
  21. IceCube-Cascade 240714A: TRT optical observations on the EP/FXT positions
  22. IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
  23. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  24. IceCube-Cascade 240626A: Upper limits from a search for additional neutrino events in IceCube
  25. IceCube-Cascade 240518A: Upper limits from a search for additional neutrino events in IceCube
  26. LIGO/Virgo/KAGRA S240422ed: Upper limits from a two-week IceCube neutrino search
  27. IceCube-240424A: GRANDMA Optical Upper Limit of Fermi J2151.3+0220
  28. Fermi-LAT gamma-ray observations of IceCube-240424A
  29. IceCube-240424A: Upper limits from a search for additional neutrino events in IceCube
  30. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  31. IceCube Alert 240424.08: Global MASTER-Net observations report
  32. IceCube-240419A: Upper limits from a search for additional neutrino events in IceCube
  33. Fermi-LAT gamma-ray observations of IceCube-240419A
  34. IceCube Alert 240419.98: Global MASTER-Net observations report
  35. IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
  36. IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
  37. IceCube-Cascade 240416A: Upper limits from a search for additional neutrino events in IceCube
  38. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  39. Fermi-LAT gamma-ray observations of IceCube-240412A
  40. IceCube Alert 240412.23: Global MASTER-Net observations report
  41. IceCube-240412A - IceCube observation of a high-energy neutrino candidate track-like event
  42. IceCube-240327B: GRANDMA/Kilonova-Catcher observations of 4FGL J0555.9+0030 and optical upper limits
  43. Fermi-LAT gamma-ray observations of IceCube-240327B
  44. Fermi-LAT gamma-ray observations of IceCube-240327A
  45. IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
  46. IceCube-240327B: Upper limits from a search for additional neutrino events in IceCube
  47. IceCube-240327A: Upper limits from a search for additional neutrino events in IceCube
  48. IceCube-240327B: No candidates from the Zwicky Transient Facility
  49. IceCube Alert 240327.68: Global MASTER-Net observations report
  50. IceCube-240327B - IceCube observation of a high-energy neutrino candidate track-like event
  51. IceCube-240327A - IceCube observation of a high-energy neutrino candidate track-like event
  52. Fermi-LAT gamma-ray observations of IceCube-240307A
  53. IceCube-240307A: Upper limits from a search for additional neutrino events in IceCube
  54. IceCube-240307A - IceCube observation of a high-energy neutrino candidate track-like event
  55. IceCube Alert 240307.32: Global MASTER-Net observations report
  56. Fermi-LAT gamma-ray observations of IceCube-240229A
  57. IceCube-240229A: Upper limits from a search for additional neutrino events in IceCube
  58. IceCube-240229A - IceCube observation of a high-energy neutrino candidate track-like event
  59. IceCube Alert 240229.66: Global MASTER-Net observations report
  60. Fermi-LAT gamma-ray observations of IceCube-240204A
  61. IceCube-240204A: Upper limits from a search for additional neutrino events in IceCube
  62. IceCube-240204A - IceCube observation of a high-energy neutrino candidate track-like event
  63. IceCube Alert 240204.38: Global MASTER-Net observations report
  64. IceCube-240123A: Upper limits from a search for additional neutrino events in IceCube
  65. Fermi-LAT gamma-ray observations of IceCube-240123A
  66. IceCube Alert 240123.48: Global MASTER-Net observations report
  67. IceCube-240123A - IceCube observation of a high-energy neutrino candidate track-like event
  68. IceCube-240105A: Detection of NIR flare of PKS 0446+11 with WINTER
  69. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240118A: correction on the localization
  70. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240118A
  71. IceCube-240105A: ZTF optical observation of blazar PKS 0446+11
  72. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 0446+11, located inside the IceCube-240105A error region
  73. IceCube-240105A: Upper limits from a search for additional neutrino events in IceCube
  74. IceCube-240105A: Three candidates from the Zwicky Transient Facility
  75. IceCube-240105A: JCMT SCUBA2 Detection of Two Bright Submillimeter Sources
  76. Update of IceCube-240105A - Corrected errors
  77. IceCube Alert 240105.52: Global MASTER-Net observations report
  78. IceCube-240105A - IceCube observation of a high-energy neutrino candidate track-like event
  79. IceCube-Cascade 231230A: Upper limits from a search for additional neutrino events in IceCube
  80. IceCube-231211A: GRANDMA observations of PKS2047+098
  81. LIGO/Virgo/KAGRA S231215i: 3 counterpart neutrino candidate events from an IceCube neutrino search
  82. IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
  83. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
  84. IceCube-231211A - IceCube observation of a high-energy neutrino candidate track-like event
  85. IceCube Alert 231211.03: Global MASTER-Net observations report
  86. IceCube-231202A: No candidates from the Zwicky Transient Facility
  87. Fermi-LAT gamma-ray observations of IceCube-231202A
  88. LIGO/Virgo/KAGRA S231205c: One counterpart neutrino candidate event from an IceCube neutrino search
  89. IceCube-231202A: Upper limits from a search for additional neutrino events in IceCube
  90. IceCube-231202A - IceCube observation of a high-energy neutrino candidate track-like event
  91. Fermi-LAT gamma-ray observations of IceCube-231125A
  92. IceCube-231125A: Upper limits from a search for additional neutrino events in IceCube
  93. Update of IceCube-231125A - Corrected errors
  94. IceCube-231125A - IceCube observation of a high-energy neutrino candidate track-like event
  95. LIGO/Virgo/KAGRA S231119u: One counterpart neutrino candidate from IceCube neutrino searches
  96. GRB 231115A: Upper limits from a neutrino search with IceCube
  97. IceCube-231103A: No candidates from the Zwicky Transient Facility
  98. IceCube-231103A: Upper limits from a search for additional neutrino events in IceCube
  99. LIGO/Virgo/KAGRA S231106y: one counterpart neutrino candidate from IceCube neutrino searches
  100. Fermi-LAT gamma-ray observations of IceCube-231103A

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